No... you'd change:
<UnitArtStyleType>UNIT_ARTSTYLE_EUROPEAN</UnitArtStyleType>
To
<UnitArtStyleType/>
Try it for ONE CIV... and check it in-game... if it makes them all super-bland, you've succeeded, then go down the list and do it for each civ in-game... I'm not 100% sure it would work, but doing that for just about every other XML command you don't want to use usually works.
Note, each civ will have a line that looks like that, and some will differ... some will say:
<UnitArtStyleType>UNIT_ARTSTYLE_EUROPEAN</UnitArtStyleType>
or
<UnitArtStyleType>UNIT_ARTSTYLE_ASIAN</UnitArtStyleType>
or
<UnitArtStyleType>UNIT_ARTSTYLE_MIDDLE_EAST</UnitArtStyleType>
etc, etc, etc...
Change each one to read:
<UnitArtStyleType/>
I believe that will work... if not, you'll have to mess around with the other file I suspect... but I'm fairly sure my 1st trick should work.
Doing this:
<UnitArtStyleType/>
Is basically telling the game you don't want to use any special ethnic group at all for that civ... if no ethnic group is used, it will default to the basic (vanilla Civ-4) units.
P.S.
You'd really hate my mod pack!